Integrated Regional Water Management Plan

Water Quality Conditions Associated with Cattle Grazing and Recreation on National Forest Lands

Title

Water Quality Conditions Associated with Cattle Grazing and Recreation on National Forest Lands

Abstract

There is substantial concern that microbial and nutrient pollution by cattle on public lands
degrades water quality,
threatening human and ecological health. Given the importance of clean water on multiple-use
landscapes, additional research is required to document and examine potential water quality issues
across common resource use activities. During the 2011 grazing-recreation season, we conducted a
cross sectional survey of water quality conditions associated with cattle
grazing and/or recreation on 12 public lands grazing allotments in California. Our specific study
objectives were to 1)
quantify fecal indicator bacteria (FIB; fecal coliform and E. coli), total nitrogen, nitrate,
ammonium, total phosphorus, and soluble-reactive phosphorus concentrations in surface waters; 2)
compare results to a) water quality regulatory benchmarks,
b) recommended maximum nutrient concentrations, and c) estimates of nutrient background
concentrations; and 3) examine relationships between water quality, environmental conditions,
cattle grazing, and recreation. Nutrient
concentrations observed throughout the grazing-recreation season were at least one order of
magnitude below levels of ecological concern, and were similar to U.S. Environmental Protection
Agency (USEPA) estimates for background water
quality conditions in the region. The relative percentage of FIB regulatory benchmark exceedances
widely varied under
individual regional and national water quality standards. Relative to USEPA’s national E. coli FIB
benchmarks–the most contemporary and relevant standards for this study–over 90% of the 743 samples
collected were below recommended criteria values. FIB concentrations were significantly greater
when stream flow was low or stagnant, water was turbid, and
when cattle were actively observed at sampling. Recreation sites had the lowest mean FIB, total
nitrogen, and soluble-
reactive phosphorus concentrations, and there were no significant differences in FIB and nutrient
concentrations between key grazing areas and non-concentrated use areas. Our results suggest cattle
grazing, recreation, and provisioning of clean
water can be compatible goals across these national forest lands.